1. Field of the Invention
The invention relates to rotary devices of the axial vane type, in which a volume change occurs between adjacent vanes and cam surfaces on each side of the rotor and in which the vanes translate axially with respect to the rotational axis of the rotor. More particularly, the present invention relates to an internally supercharged and turbocharged axial vane rotary device and a method for vane actuation in axial vane rotary devices.
2. Description of Related Art
A typical prior art axial vane rotary device (e.g. U.S. Pat. No. 5,429,084 to Cherry et al.) comprises an external stator enclosing a cylindrical chamber having an annular outer wall and end walls. Each end wall has an axially undulating cam surface parallel with respect to the other end so that high portions of the cam surface of one end align with low portions of the cam surfaces at the opposite end. A rotor is rotatably mounted within the chamber. The rotor has an annular outer wall and a plurality of angularly spaced apart, axially extending slots extending therethrough. A vane is slidably received in each slot. The vanes reciprocate axially and alternately expand and contract volumes between adjacent vanes and the axially undulating end walls as the rotor rotates. Each axially undulating end wall has alternating first and second portions. The second portions are further away from the rotor than the first portions. The first portion of one end wall is aligned with a second portion of the opposite end wall so that the axial distance between them remains constant. The slots extend radially outwards on the rotor to the outer wall thereof. The outer end of each vane slidably engages the annular outer wall of the stator. The outer wall of the stator may have a guide cam and vanes may have a follower received by the guide cam. The guided cam is shaped to cause the vanes to reciprocate axially with respect to the rotor as the rotor rotates. Each vane may have resiliently biased first seals extending along the inner edge and second seals along end edges thereof.
In the above prior art, as the rotor rotates, the vanes move outward due to centrifugal force and make sliding contacts on the annular outer wall, which may be lubricated by an oil film, and the side edges of the vanes make sliding contact with the axially undulating cam surfaces, thus causing the vane to reciprocate as the rotor rotates. This arrangement is adequate in a small axial vane rotary device or in one operating at low speed with provision for appropriate lubrication at the outer and side edges of the vanes. In axial rotary devices that are large or that operate at high speed, excessive centrifugal forces and shear forces cause large outer and edge tip loading of the vanes and result in excessive wear and damage to wall surfaces and vanes. In effort to overcome these problems, the reciprocating motion of the vane is actuated by a pin projecting from the vane, equipped with an anti-friction shoe, as the follower that is received by the guide cam. Although this arrangement alleviates the outer and side tip loading by conveying such loading to the pin, the pin itself often can not withstand such large friction forces without breaking.
In the above prior art, the intake and exhaust ports comprise passages through the undulating end walls. This arrangement makes the fabrication of such surfaces more complex.
In the above prior art, the design of the engine does not permit inclusion of internal supercharging or turbo-charging capability and thereby any such charging has to be performed externally. The advantage of internal super- and turbo-charging is the efficient utilization of space and a reduction of pressure losses associated with conduit inter-connection, as well the reduction of the complexity associated with such inter-connection.